Circuit breaker



Jan. 7, 1936. w. M. AUSTIN CIRCUIT BREAKER Filed Nov. 29, 1933 3 Sheets-Sheet l 1 fi "g2 iy u 1 //4 a5 is ,1 is

4" I ago IN VENTOR Wa/fer/W. iusf/n.

WITNESSES:

Jan. 7, 1936.

I w. M. AUSTIN 2,027,219

CIRCUIT BREAKER Filed Nov. 29, 1935 3 Sheets-Sheet 2 WITNESSES: INVENTOR W WM ATTO EY Jan. 7, 1936. w s nN 2,027,219

CIRCUIT BREAKER Filed Nov. 29, 1933 3 Sheets-Sheet 3 WITNESSES: INVENTOR h/a/fer-M $577)).

Patented Jan. 7, 1936 UNITED STATES PATENT orrlca BREAKER Pennsylvania Application November 29, 1933, Serial No. 700,278

17 Claims.

My invention relates, generally, to circuit opening devices or circuit breakers and it has particular relation to are extinguishing devices therefor.

The object of my invention, generally stated, is

to provide a circuit breaker which shall be simple and eficient in operation and which may be readily and economically manufactured and installed.

The principal object of my invention is to provide for drawing an arc between contact members within a radial field and rotating the are by means of the radial field until it is extinguished.

Another object of my invention is to provide for compensating for the unsymmetrical shape of a pole piece located along contact members of a circuit breaker in order to provide a substantially uniform reluctance for a radial arc extinguishing field.

Still another object of my invention is to provide an inherently symmetrical magnetic circuit for the radial field of an arc extinguishing device in which the arc is drawn within the radial field.

A further object of my invention is to provide for reducing the likelihood of an insulation breakdown in an arc extinguishing device used in con junction with a circuit breaker while still maintaining the ventilation characteristics thereof.

other objects of my invention will in part be obvious and in part appear hereinafter.

My invention accordingly is disclosed in the embodiment hereof shown in the accompanying drawings and comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the na-:

ture and scope of my invention, reference may be had to the following detailed description taken in connection with the accompanying drawings, in which:

Figure 1 is a view, partly in side elevation and partly in section taken along the line 1-1 of Fig. 2, showing one modification of my -invention; v

Fig.2 is a sectional view taken along line 11-11 of the arc extinguishing device illustrated in Fig. 1;

Figs. 3 and 4 illustrate details forming part of the structure of the arc extinguishing device illustrated in Fig. 1;

Fig. 5 is a view partly in side elevation and partly in section taken along the line V-V of Fig. 6 showing another modification of my inventlon;

drawings, the reference character designates.

an insulating panel upon which main contact members it and H of a circuit interrupter may be mounted in the usual manner. In order to bridge the main contact members it) and H a main bridging contact member 58 is provided.

which may be actuated by means of a closing mechanism, illustrated in part at 89. Since the closing mechanism does not constitute a part of this invention, only a sufiicient portion thereof is shown to illustrate the manner in which my invention may be practiced.

The customary secondary contact members 2% and 22 are provided which are arranged to separate after the main bridging contact member as has been disengaged from the contact members it and il. However, the circuit is finally broken between a stationary arcing contact member 23 and a movable arcing contact member 25, which is carried by means of an arm 25 supported by the closing mechanism 99, as shown.

In order to extinguish the arc which is drawn mtween the contact members 23 and 2% very quickly, the arc extinguishing structure, illustrated generally at 26, is provided. The structure 2t comprises a cylindrical member or shell 23? of magnetic material such as iron which is provided with interior threads 28 and 29 at the ends thereof. as illustrated. The threads 28 serve to engage a base plate 3!, also of magnetic material such as iron which may be secured by any suitable means to the panel I5. Within the shell 21, a series of metal plates 32 are positioned. These plates 32 are illustrated more clearly in Fig. 3 of the drawings and are preferably composed of non-magnetic material such as copper. The innermost plate 32 is connected, as illustrated, to the contact member 23 in order to complete the arc extinguishing circuit. Each of the plates 32 is provided with a slot 33 positioned as illustrated in Fig. 3, or degrees from that position, in order to reduce the flow of eddy currents to a minimum.

The plates 32 are disposed in insulated spaced relationship by means of large circular insulating washers 34 at the outer periphery thereof and by means of insulating washers 35, illustrated more clearly in Fig. 4 of the drawings, positioned around a central opening 36in the plates 32.

. around the openings through the openings The central opening 36 is provided with a gradually narrowing slot portion av which serves to rapidly break up the single are drawn between the contact members 23 and 25 into a series of short arcs between the plates 32.

In order to prevent the are from restriking 37 through the plates after it has begun to rotate around its original path, the insulating washer 35 is provided with a horn portion 38. With the horn portion 33 in the position illustrated, the rotating arc is guided through the plates and there is no likelihood that the main arc will be restruck due to the short arcs cog into contact with the ionized gases between the separated contacts.

With a view to rotating the are which isformed on the separation of contact members 23 and between the plates 32, a winding 39 is provided adjacent to the base plate 35, as illustrated, and is insulated therefrom. The outer te oi the winding 39 contact member the. winding 39 contact member it while the inner terminal of is connected to the stationary 23. It will be readily understood that current will flow through the winding 39 as soon as the contactmembers 2i and 22 have been opened and that, as a result, a radial field, as indicated by the dotted lines 353a, will be generated thereby which will cause the arc to rotate between the plates 32.

In order to provide for more uniformly distributing the radial field, which is generated by the winding 39, a pole piece id, of magnetic material such as iron, is provided along side the contact members 23 and 2d and is insulated therefrom by means or an insulating shell '35 As illustrated, the pole piece so is of a semi-cylin drical shape in order to permit the positioning thereof along side the contact members 23 and 52d. Because of the unsymmetrical shape oi the pole piece 2d within the shell ii, the reluctance of the magnetic circuit of the arc extinguishing device is considerably unbalanced. In order to overcome this undesirable condition slots d2 are cut in the side of the shell 2'3 adjacent to the pole piece it so that the reluctance oi the magnetic circuit to the radial field generated by the winding 39 may be substantially uniform throughout its entire extent.

A cylindrical shell of insulating material 33 is provided around the plates 32 in order to insulate them from the metal shell 2? which may be maintained at the same potential as the contact member 23. As a further precaution, an insulating disk M is provided on top of the last plate 32 and a. threaded ring 55 is screwed into the threads 29 of the shell 21 in order to clamp the various parts of the arc extinguishing structure 2B in position. It will also be observed'that a flexible shunt i5 is provided to connect the outside plate 32 to the moving contact member 26 in order to complete the circuit for the are extinguishing device 26 and thereby maintain the are within the said device tact member 24 swings last plate 32.

Inoperation, as soon as contact members 2i and 22 are separated, current is caused to flow through the winding 39, thereby setting up the radial magnetic field indicated by the dotted lines 39a. between the pole piece to and the shell 27. The are which is formed on the separation of the and 25 is moved upwardly because of the radial field tending to move it in is connected to the stationary ably of crescent shape, is carried plates 53, 55

when the moving con-. outwardly beyond the of the interaction of the radial field set up by the winding 39 between the plates 32 and the several arcs. It will be understood that the several arcs are caused to rotate around the path indicated by the dotted line 456 until they are extinguished.

Referring now particularly to Figs. 5 through 14 of the drawings, it will be observed that a modification of the arc extin apparatus or device is there illustrated. It is desirable to avoid the unsymmetrical magnetic circuit, which has been heretofore illustrated order to simplify the construction of the device. In addition, it is also desirable to provide for ventilating the are extinguishing structure in .order to increase its arc rupturing capacity.

As illustrated in Fig. 5 of the drawings, an arc extinguishing device, illustrated generally at 55, is provided which comprises a front clamping plate 5i and a back clamping plate 52, both of insulating material. Between the clamping plates 5! and 52, a series of plates 5d, and 55 are provided which are more clearly illustrated in Figs. l2, l3, and 14, respectively. Each of the plates 53, 56, and 55 is provided with an opening 5t, 57, and 5d, respectively, which is diflerently shaped for a purpose which will be forth hereinafter.

Within the openings 56, 5'5, and 58, a pole piece 55., of magnetic material is provided and is surrounded by a cylindrical shell lid of insulating material. At the base of the pole piece 59, a fixed contact member 8'2 is provided which is connected to the innermost plate 53 and by means of a conductor E3 to the contact member 2 l, as illustrated. A movable contact member 5d, preferby means of the arm 25 to engage the fixed contact member 62. A flexible shunt $5 is provided for connecting the movable contact member 65 to the outside plate 55, asshown.

With a view to providing a radial field to cause they are which is formed between contact members 62 and 65 to travel along a path indicated by the dotted line 66, a winding 67 is positioned between the pair of plates 54], the terminals of the winding 6'! being connected to the adjacent plates 55, as shown in the drawings. The radial field generated by the winding t? is indicated in Figs. 5 and 6 by the dotted lines to.

It is desirable to reduce the reluctance of the magnetic circuit of the arc extinguishing device so to a minimum. For this purpose, magnetic and described, in

material comprising a series of iron or steel studs it! is provided around the periphery of the and 55. As is more clearly illustrated in Fig. 7 of the drawings, each of the studs 70 is provided with aninsulating casing ll which is formed entirely around thestud it. These studs are insulated in this manner in order to prevent a breakdown of the insulation across the stack of plates when the arc is drawn. Each of the plates 5! and 52 is provided with suitable recesses 73 and M respectively, in which the ends of the insulated studs ill may be positioned and between which they may be securely clamped. It will be observed that the peripheries of the plates 53, 5d, and 55 are scalloped in order to provide for interfitting with theinsulated studs 70.

As set forth hereinbefore, it is desirable to provide for ventilation between the plates 53, 54, and 55 in order to increase the rupturing capacity of the arc extinguishing device 50. For this purpose, these plates are spaced apart by means or a ring 15 of insulating material, a section of which is shown in Figs. 8 and 9 of the drawings. The rings 15 are positioned around the insulated studs "HI, as illustrated, and slotted openings 16 therebetwe'en provide passages for the rapid removal of the hot gases which are formed in the process of extinguishing an arc.

In order to prevent the are from entering between the plates 53, 54, and 55, except at a predetermined position, two oppositely disposed insulating sleeves 11, shown more clearly in Figs. 10 and 11, are provided along the peripheries of the openings 56, 51 and 58 in the plates 53, 54, and 55. The sleeves 11 are oppositely positioned since the plates 53 and 51 are oppositely positioned on the corresponding sides of the winding G1 because the short arcs are rotated in opposite directions.

In operation, after the contact members 2| and 22 have become separated, an arc is drawn between the fixed contact member 52 and the movable contact member 5|. The are thus formed is caused to transfer from the moving contact member 64 to the inside plate 5! as the movable contact member 64 moves past it. The are is again transferred to the moving contact member 66 as it passes the outside plate 54. It will be readily apparent that current will be caused to how through the winding 61! and that a radial magnetic field will be generated between the pole piece 59 and the studs id.

it will also be apparent that the direction of the magnetic field on the left hand sideoi the winding iii, as viewed in Fig. 5, is opposite to its direction on the right hand mde. For this reason, the plates 53 on the left hand side are provided with the opening 55 having a wedge.

shaped slot 18 opening in one direction while the opening "58 in the plates 55 on the opposite side of the winding 5'! is provided with a. correspondingly oppositely positioned slot Thus, on the left hand side of the winding iii, the several arcs are caused to rotate in one direction while on the right hand side, the several arcs are caused to rotate in an opposite direction. Because of the fact that it is desired to transfer the arc to and from the plates 55, the opening Si is provided therein so that only mechanical clearance is provided between the tips 86 and iii of the crescent shaped movable contact member E54.

While the winding 6? is illustrated as being connected between the plates 54, it will be readily apparent that the terminals thereof may be connected between the contact members 2| and 62 for the purpose of establishing the radial field as soon as the contact members 2! and 22 are separated rather than delaying the generation thereof until the contact member 64 has moved past the outside plate 54.

Since certain further changes may be made in the above construction and difierent embodiments of the invention may be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. In electric circuit interrupting apparatus,

in combination, means between which an arc may be established, a plurality of spaced metal plates surrounding the means for establishing the arc and disposed at right angles to the direction of the arc to provide an annular path for the arc, means rality of spaced metal plates surrounding one.

of the contact members and disposed at right angles to the direction of relative movement thereof to provide an annular path for the are drawn between the contact members, a winding connected to be energized when the arc is drawn between the contact members and disposed substantially co-axially therewith for generating a magnetic field radially between the plates,- thereby causing the arc to travel along an annular path between the plates, means oi insulating material extending entirely around the periphery of the annular path to prevent movement of the arc therefrom, and said means of insulating material permitting outward flow oi fluid from between the plates.

3. In electric circuit interrupting apparatus, in combination, means for causing an arc to be established, a plurality of spaced metal plates havi102; openings therethrough in which said arc is 35 initially established by said means and disposed at right angles to the are to provide an annular path for the are, said openings through the plates being positioned inside of the inner periphery of said annular path, a pair of magnetic means disposed on opposite sides of the arc establishing means, and a winding connected to be energized when the arc is established and disposed substantially co-axially therewith for generating a magnetic field in the magnetic circuit means and radially across the annular path and across the openings through the plates, thereby causing the arc to travel along the annular path between the plates.-

4. in electric circuit interrupting apparatus, in combination, means between which an arc may be initially established, a pole piece comprising magnetic material disposed in insulated spacedrelation along the path where the arc is initially established, a plurality of spaced metal plates disposed substantially co-axially around the path where the arc is initially established and substantially co-axially around the pole piece and at right angles thereto, and means for energizing 'said pole piece and generating a substantially uniform radial magnetic field between the plates when the arc is drawn for causing the arc to traverse an annular path thereoetween, said annular path extending around the outside of both said means for establishing the arc and said pole piece.

5. In electric circuit interrupting apparatus, in combination, a pair of separable contact members between which an arc may be drawn to finally interrupt the circuit, a pole piece comprising magnetic material disposed in insulated spaced relation along the path of relative movement of the contact members, a'plurality of spaced metal plates disposed substihitially co-axially around one of the contact members and the pole piece and at right angles thereto, said metal plates providing an annular path for the are around the outside of both said pole piece and said contact member, a frame of magnetic material disposed around said plates in such relation relative to the pole piece as to provide a magnetic circuit having substantially uniform reluctance around the annular path, and means for generating a radial magnetic field between the pole piece and the frame and between the plates when the arc is drawn, thereby causing the arc to travel along the annular path between the plates.

6. In electric circuit interrupting apparatus, in combination, a pair of separable contact members between which an arc may be drawn, an asymmetrical pole piece comprising magnetic material disposed in insulated spaced relation along the path of relative movement of the contact members, a, plurality of spaced metal plates disposed substantially co-axially around one of the contact members and the pole piece and at right angles thereto and providing an annular path for the arc, means of magnetic material disposed in insulated spaced relation around the metal plates, portions of said means of magnetic material being of difierent reluctance than other portions thereof to equalize the reluctance of the magnetic circult, around the annular path for the arc, and means for creating a radial magnetic field between the pole piece and the means of magnetic material and between the plates, when the are is drawn, thereby causing the arc to travel along the annular path between the plates.

7. In electric circuit interrupting apparatus, in

- combination, a pair of separable contact members between which an arc may be drawn, a pole piece comprising magnetic material disposed in insulated spaced relation along the path of relative movement of the contact members, a pluralityof spaced metal plates disposed substantially co-axially around one of the contact members and the pole piece and at right angles there to, a cylindrical frame of magnetic material disposed asymmetrically relative to said pole piece and in insulated spaced relation around the metal plates, portions of said frame adjacent to the pole piece being removed on one side only to equalize the reluctance of the magnetic structure, and a winding connected to be energized on separation of the contact members when the arc is drawn and disposed co-axially with said metal plates for generating a radial magnetic field therebetween, thereby causing the arc to traverse an annular path between extinguished.

8. In a circuit interrupter, a plurality of conducting plates, having spaces therebetween, an opening through said plates, means in said opening for establishing the arc therein, said plates providing an annular path extending around the outside of said opening, and means of insulating material defining the complete outer periphery of said annular path for retaining the are thereon, and said means of insulating material permltting the escape of gas outwardly from the annular path. I H 9. In an electric circuit breaker, in combination, a fixed and a movable contact member between which an armmay be drawn, a plurality of spaced metal plates having openings therein for the moving contact member and disposed at right angles to the direction of movement thereof for subdividing the arc into a series of short arcs, said plates having an annular arc path extending around the outside of said openthe plates until it is of short arcs,

ings, and a winding connected to be energized when the arc is drawn between the contact mem'- bers and disposed substantially co-axlally therewith for generating a radialmagnetlc field between the plates, thereby causing the several arcs to traverse the annular path between the plates surrounding the path of the movable contact member through said openings, and means of insulating material defining the complete outer periphery of said annular path for retaining the arc thereon, lating material outwardly from the annular path.

10. In an electric circuit breaker, in. combination, means for establishing an are, a plurality of spaced metal plates having an opening into which the means for establishing the arc extends and disposed at right angles to the are for subdividing the are into a series of short arcs, magnetic means extending along and closely adjacent to said means for establishing the arc, said plates providing an annular path for the are extending around the outside of the outer periphery of both said magnetic means and said opening for the means for establishing the are, and a winding connected to be energized when the are is established and disposed substantially co-axially therewith for generating a magnetic field in the magnetic means and radially between the plates, thereby causing the several arcs to traverse the annular path between the plates.

11. In an electric circuit breaker, in combination, a fixed and a movable contact member between which an arc may be drawn, a pole piece comprising magnetic material disposed in insulated spaced relation closely adjacent to the path of the movable contact member, a plurality of spaced metal plates having annular arc paths disposed around the outside of both the movable contact member and the angles thereto for subdividing the are into a series of short arcs, and means for generating a pole piece and at right and said means of insupermitting the escape of gas substantially uniformradial magnetic field between the plates when the arc is drawn, thereby causing the several arcs to traverse the annular path between the plates surrounding the path of the movable contact member and the pole piece.

12. In an electric circuit breaker, in combination,'means to establish an are, a pole piece comprising magnetic material disposed in insulated spaced relation along the path of the arc. a plurality of spaced metal plates disposed around the pole piece and at right angles thereto for subdividing the are into a series of short arcs, a magnetic structure disposed asymmetrically relative to said pole piece around said plates, said magnetic structure and said pole piece having portions of different vreluctances to provide a magnetic circuit having substantially uniform reluctance across said plates, and means for generating a radial magnetic field between the pole piece and the magnetic structure and between the plates when the arc is drawn, thereby causing the sevcral arcs to traverse an annular path between the plates.

13. In electric circuit interrupting apparatus, in combination, a pole piece, a fixed and a movable contact member between which an arc may be drawn, theaxls of the path of the movable contact member being substantially coincident with the axisof the pole piece, a plurality of spaced metal pole piece for subdividing the are into a series and means to cause the several plates coaxially surrounding the arcs to traverse an annular path between the plates.

14. In electric circuit interrupting apparatus, in combination, a pole piece, a fixed and a movable contact member between which an arc may be drawn, the axis of the path of the movable contact member being substantially coincident with the axis of the pole piece, a plurality of spaced metal plates co-axially surrounding the pole piece for subdividing the are into a series of short arcs, a plurality of insulated members comprising magnetic material extending transversely to the plates and spaced apart along the periphery thereof for reducing the reluctance of the magnetic circuit, and a winding connected to be energized when the arc is drawn between the contact members and disposed coaxially with the pole piece for generating a magnetic field radially between the plates, thereby effecting the rotation of the several arcs along an annular path between the plates and around the outside of the path of the movable contact member.

15. In electric circuit interrupting apparatus, in combination, a pole piece comprising magnetic material, a fixed and a movable contact member between which an arc may be drawn, the fixed contact member being disposed at the base of the pole piece and the movable contact member having a crescent-shaped cross-section disposed around the pole piece, a plurality of spaced metal plates surrounding the path of the movable contact member and disposed co-axially with the pole piece for subdividing the are into a series of short arcs, and means to cause the several arcs to transverse an annular path between the plates.

16. In an electric circuit breaker, in combination, a pole piece comprising magnetic material, a fixed and a movable contact member between which an arc may be drawn, the fixed contact member being disposed at the base of the pole piece and the movable contact member having a crescent-shaped cross-section disposed in operative relation to the fixed contact member and symmetrically around the pole piece, a plurality of spaced metal plates surrounding the 5 path of the movable contact member and disposed co-axially with the pole piece for subdividing the are into a series of short arcs, and

a winding connected tobe energized when the arc'is drawn between the contact members and disposed co-axially with the pole pieces for generating a magnetic field radially between the plates, thereby effecting the rotation of the several arcs along an annular path between the plates and around the path of the movable contact member.

17. In electric circuit interrupting apparatus, in combination, a pole piece of cylindrical shape comprising magnetic material, a fixed and a movable contact member between which an arc may be drawn, the fixed contact member being disposed at the base of the pole piece and the movable contact member having a crescentshaped cross-section disposed in operative relation to the fixed contact member and symmetrically around the pole piece, a plurality of circular spaced metal plates surrounding the path of the movable contact member and disposed coaxially with the pole, piece for subdividing the are into a series of short arcs, a plurality of insulated members comprising magnetic material extending transversely to the plates and spaced apart along the periphery thereof for reducing the reluctance of the magnetic circuit, and a winding connected to be energized when the are is drawn between the contact members and disposed co-axially with the pole piece for generating a magnetic field radially between the plates, thereby causing the several arcs to traverse an annular path between the plates and around the path of the movable contact member.

WALTER M. AUSTIN. 

